A computational first principles investigation on the structural, elastic, electronic and optical characteristics of the ternary alloys ScxLu1-xN

This study investigates the structural, elastic, electronic, and optical properties of the stable phase of ScN and LuN materials and their mixed ternary alloys, formulated as Sc_xLu_1-xN, 0 ≤ x ≤ 1. This study uses the full potential linearized augmented plane wave technique within the density functional theory system and is performed using the WIEN2k computational package for crystalline solids. Based on our computational work carried out using the Wu and Cohen generalized gradient approach for the exchange-correlation function, we find that the structural variables of the alloys generally follow the Vegard's law. The elastic stability is confirmed using the computational data for elastic constants by applying Born's criteria. The determinations show that all tested alloys are brittle and are classified as hard materials. The band structure evaluation shows that the mixed alloys exhibit a direct band gap at Γ–Γ, while their binary counterparts have an indirect band gap at Γ–X. Moreover, the band gap energy of the alloy Sc_xLu_1-xN shows a nonlinear response with changes in the x concentration. Additionally, optical variables such as the refractive index, absorption coefficient, optical conductivity and loss functions have been enumerated and discussed. Some qualitative conclusions have been drawn regarding these alloys.